F-Divergences and Cost Function Locality in Generative Modelling with Quantum Circuits

Autor: Louis Sharrock, Brian Coyle, Chiara Leadbeater, Marcello Benedetti
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Entropy; Volume 23; Issue 10; Pages: 1281
Entropy, Vol 23, Iss 1281, p 1281 (2021)
Entropy
ISSN: 1099-4300
DOI: 10.3390/e23101281
Popis: Generative modelling is an important unsupervised task in machine learning. In this work, we study a hybrid quantum-classical approach to this task, based on the use of a quantum circuit Born machine. In particular, we consider training a quantum circuit Born machine using $f$-divergences. We first discuss the adversarial framework for generative modelling, which enables the estimation of any $f$-divergence in the near term. Based on this capability, we introduce two heuristics which demonstrably improve the training of the Born machine. The first is based on $f$-divergence switching during training. The second introduces locality to the divergence, a strategy which has proved important in similar applications in terms of mitigating barren plateaus. Finally, we discuss the long-term implications of quantum devices for computing $f$-divergences, including algorithms which provide quadratic speedups to their estimation. In particular, we generalise existing algorithms for estimating the Kullback-Leibler divergence and the total variation distance to obtain a fault-tolerant quantum algorithm for estimating another $f$-divergence, namely, the Pearson divergence.
Comment: 20 pages, 9 figures, 4 tables
Databáze: OpenAIRE